First Trust Bloomberg Emerging Market Democracies ETF Investment Risks - First Trust Bloomberg Emerging Market Democracies ETF	Sep. 30, 2025
Asia Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	ASIA RISK. The Fund is subject to certain risks specifically associated with investments in the securities of Asian issuers. Many Asian economies have experienced rapid growth and industrialization, and there is no assurance that this growth rate will be maintained. Some Asian economies are highly dependent on trade, and economic conditions in other countries within and outside Asia can impact these economies. Certain of these economies may be adversely affected by trade or policy disputes with its major trade partners. There is also a high concentration of market capitalization and trading volume in a small number of issuers representing a limited number of industries, as well as a high concentration of investors and financial intermediaries. Certain Asian countries have experienced and may in the future experience expropriation and nationalization of assets, confiscatory taxation, currency manipulation, political instability, armed conflict and social instability as a result of religious, ethnic, socio-economic and/or political unrest. In particular, escalated tensions involving North Korea and any outbreak of hostilities involving North Korea could have a severe adverse effect on Asian economies. Governments of certain Asian countries have exercised, and continue to exercise, substantial influence over many aspects of the private sector. In certain cases, the government owns or controls many companies, including the largest in the country. Accordingly, government actions could have a significant effect on the issuers of the Fund’s securities or on economic conditions generally. Recent developments in relations between the U.S. and China have heightened concerns of increased tariffs and restrictions on trade between the two countries. An increase in tariffs or trade restrictions, or even the threat of such developments, could lead to a significant reduction in international trade, which could have a negative impact on the economy of Asian countries and a commensurately negative impact on the Fund.
Authorized Participant Concentration Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
Cash Transactions Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	CASH TRANSACTIONS RISK. The Fund expects to effect a significant portion of its creations and redemptions for cash rather than in-kind, which would cause it to incur related costs and expenses. As a result, an investment in the Fund may be less tax-efficient than an investment in an ETF that effects all of its creations and redemptions in-kind. Because the Fund may effect redemptions for cash, it may be required to sell portfolio securities in order to obtain the cash needed to distribute redemption proceeds. A sale of portfolio securities may result in capital gains or losses and may also result in higher brokerage costs.
Currency Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	CURRENCY RISK. Changes in currency exchange rates affect the value of investments denominated in a foreign currency, and therefore the value of such investments in the Fund’s portfolio. The Fund’s net asset value could decline if a currency to which the Fund has exposure depreciates against the U.S. dollar or if there are delays or limits on repatriation of such currency. Currency exchange rates can be very volatile and can change quickly and unpredictably. As a result, the value of an investment in the Fund may change quickly and without warning.
Current Market Conditions Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has begun to lower interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including high interest rates, declining valuations and elevated vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes, including the imposition of tariffs, and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
Cyber Security Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	CYBER SECURITY RISK. The Fund is susceptible to operational, information security and related risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity, any of which could result in a material adverse effect on the Fund or its shareholders. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. Emerging threats like ransomware or zero-day exploits could also cause disruptions to Fund operations. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, among many other third-party service providers, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Further, errors, misconduct, or compromise of accounts of employees of the Fund or its third-party service providers can also create material cybersecurity risks. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers. Cyber security incidents may also trigger Fund obligations under data privacy laws, potentially increasing notification and compliance burdens. Cyber security incidents affecting issuers in whose securities the Fund invests may also have a negative impact on the value of the securities of such issuers, and in turn, the value of the Fund.
Depositary Receipts Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	DEPOSITARY RECEIPTS RISK. Depositary receipts represent equity interests in a foreign company that trade on a local stock exchange. Depositary receipts may be less liquid than the underlying shares in their primary trading market. Any distributions paid to the holders of depositary receipts are usually subject to a fee charged by the depositary. Holders of depositary receipts may have limited voting rights, and investment restrictions in certain countries may adversely impact the value of depositary receipts because such restrictions may limit the ability to convert the equity shares into depositary receipts and vice versa. Such restrictions may cause the equity shares of the underlying issuer to trade at a discount or premium to the market price of the depositary receipts.
Emerging Markets Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	EMERGING MARKETS RISK. Investments in securities issued by companies operating in emerging market countries involve additional risks relating to political, economic, or regulatory conditions not associated with investments in securities and instruments issued by U.S. companies or by companies operating in other developed market countries. Investments in emerging markets securities are generally considered speculative in nature and are subject to the following heightened risks: smaller market capitalization of securities markets which may suffer periods of relative illiquidity; significant price volatility; restrictions on foreign investment; possible repatriation of investment income and capital; rapid inflation; and currency convertibility issues. Emerging market countries also often have less uniformity in accounting, auditing and reporting requirements, unsettled securities laws, unreliable securities valuation and greater risk associated with custody of securities. Financial and other reporting by companies also may be less reliable in emerging market countries. Shareholder claims that are available in the U.S., as well as regulatory oversight and authority that is common in the U.S., including for claims based on fraud, may be difficult or impossible for shareholders of securities in emerging market countries or for U.S. authorities to pursue. The Index the Fund seeks to track may not weight the securities in emerging market countries on the basis of investor protection limitations, financial reporting quality or available oversight mechanisms. Furthermore, investors may be required to register with the government of an emerging market country the proceeds of sales of securities and future economic or political crises could lead to price controls, forced mergers, expropriation or confiscatory taxation, seizure, nationalization or creation of government monopolies.
Equity Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	EQUITY SECURITIES RISK. The value of the Fund's shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
Financial Companies Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	FINANCIAL COMPANIES RISK. Financial companies, such as retail and commercial banks, insurance companies and financial services companies, are especially subject to the adverse effects of economic recession, currency exchange rates, extensive government regulation, decreases in the availability of capital, volatile interest rates, portfolio concentrations in geographic markets, industries or products (such as commercial and residential real estate loans), competition from new entrants and blurred distinctions in their fields of business.
Index Concentration Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by it, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
Index Or Model Constituent Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
Index Provider Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
Information Technology Companies Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	INFORMATION TECHNOLOGY COMPANIES RISK. Information technology companies produce and provide hardware, software and information technology systems and services. These companies may be adversely affected by rapidly changing technologies, short product life cycles, fierce competition, aggressive pricing and reduced profit margins, the loss of patent, copyright and trademark protections, cyclical market patterns, evolving industry standards and frequent new product introductions. In addition, information technology companies are particularly vulnerable to federal, state and local government regulation, and competition and consolidation, both domestically and internationally, including competition from foreign competitors with lower production costs. Information technology companies also heavily rely on intellectual property rights and may be adversely affected by the loss or impairment of those rights.
International Closed Market Trading Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	INTERNATIONAL CLOSED MARKET TRADING RISK. Because securities held by the Fund trade on non-U.S. exchanges that are closed when the Fund’s primary listing exchange is open, there are likely to be deviations between the current price of an underlying security and the last quoted price for the underlying security (i.e., the Fund’s quote from the closed foreign market) used for purposes of calculating the Fund's net asset value, resulting in premiums or discounts to the Fund’s net asset value that may be greater than those experienced by other exchange-traded funds. In addition, shareholders may not be able to purchase and sell shares of the Fund on the listing exchange for the Fund, on days when the net asset value of the Fund could be significantly affected by events in the relevant foreign markets.
Large Capitalization Companies Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	LARGE CAPITALIZATION COMPANIES RISK. Large capitalization companies may grow at a slower rate and be less able to adapt to changing market conditions than smaller capitalization companies. Thus, the return on investment in securities of large capitalization companies may be less than the return on investment in securities of small and/or mid capitalization companies. The performance of large capitalization companies also tends to trail the overall market during different market cycles.
Latin America Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	LATIN AMERICA RISK. The economies of Latin American countries have in the past experienced considerable difficulties, including high inflation rates, high interest rates, high unemployment, government overspending and political instability. International economic conditions, particularly those in the United States, Europe and Asia, as well as world prices for oil and other commodities may also influence the development of Latin American economies. Many Latin American countries are highly reliant on the exportation of commodities and their economies may be significantly impacted by fluctuations in commodity prices and the global demand for certain commodities. Investments in Latin American countries may be subject to currency risks, such as restrictions on the flow of money in and out of a country, extreme volatility relative to the U.S. dollar, and devaluation, all of which could decrease the value of investments in Latin American companies. Other Latin American investment risks may include inadequate investor protection, less developed regulatory, accounting, auditing and financial standards, unfavorable changes in laws or regulations, natural disasters, corruption and military activity. The governments of many Latin American countries may also exercise substantial influence over many aspects of the private sector, and any such exercise could have a significant effect on companies in which the Fund invests. Securities of companies in Latin America may also be subject to significant price volatility.
Liquidity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	LIQUIDITY RISK. The Fund may hold certain investments that may be subject to restrictions on resale, trade over-the-counter or in limited volume, or lack an active trading market. Certain investments held by the Fund that trade on non-U.S. exchanges may be further subject to liquidity risk due to foreign market closures or unexpected impediments to trading on local markets. Accordingly, the Fund may not be able to sell or close out of such investments at favorable times or prices (or at all), or at the prices approximating those at which the Fund currently values them. Illiquid securities may trade at a discount from comparable, more liquid investments and may be subject to wide fluctuations in market value and the bid/ask spread on the Fund's shares may widen.
Market Maker Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market makers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
Mid Capitalization Companies Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	MID CAPITALIZATION COMPANIES RISK. Mid capitalization companies may be more vulnerable to adverse general market or economic developments and thus may experience greater price volatility than more established large capitalization companies. Securities of mid capitalization companies may also be less liquid than securities of large capitalization companies and may have more limited trading volumes. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.
Non Correlation Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. The Fund expects to effect a significant portion of creations and redemptions of the Funds shares in cash, which would cause it to incur related costs and expenses. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
Risk Nondiversified [Member]
Prospectus [Line Items]
Risk [Text Block]	NON-DIVERSIFICATION RISK. The Fund is classified as “non-diversified” under the 1940 Act. As a result, the Fund is only limited as to the percentage of its assets which may be invested in the securities of any one issuer by the diversification requirements imposed by the Internal Revenue Code of 1986, as amended. The Fund may invest a relatively high percentage of its assets in a limited number of issuers. As a result, the Fund may be more susceptible to a single adverse economic or regulatory occurrence affecting one or more of these issuers, experience increased volatility and be highly invested in certain issuers.
Non US Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	NON-U.S. SECURITIES RISK. Non-U.S. securities are subject to higher volatility than securities of domestic issuers due to possible adverse political, social or economic developments, restrictions on foreign investment or exchange of securities, capital controls, lack of liquidity, currency exchange rates, excessive taxation, government seizure of assets, the imposition of sanctions by foreign governments, different legal or accounting standards, and less government supervision and regulation of securities exchanges in foreign countries.
Operational Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. These errors or failures may adversely affect the Fund’s operations, including its ability to execute its investment process, calculate or disseminate its NAV or intraday indicative optimized portfolio value in a timely manner, and process creations or redemptions. The Fund relies on third-parties for a range of services, including custody, valuation, administration, transfer services, securities lending and accounting, among many others. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
Passive Investment Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
Preferred Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	PREFERRED SECURITIES RISK. Preferred securities combine some of the characteristics of both common stocks and bonds. Preferred securities are typically subordinated to bonds and other debt securities in a company’s capital structure in terms of priority to corporate income, subjecting them to greater credit risk than those debt securities. Generally, holders of preferred securities have no voting rights with respect to the issuing company unless preferred dividends have been in arrears for a specified number of periods, at which time the preferred security holders may obtain limited rights. In certain circumstances, an issuer of preferred securities may defer payment on the securities and, in some cases, redeem the securities prior to a specified date. Preferred securities may also be substantially less liquid than other securities, including common stock.
Premium Discount Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
REIT Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	REIT RISK. REITs typically own and operate income-producing real estate, such as residential or commercial buildings, or real-estate related assets, including mortgages. As a result, investments in REITs are subject to the risks associated with investing in real estate, which may include, but are not limited to: fluctuations in the value of underlying properties; defaults by borrowers or tenants; market saturation; changes in general and local operating expenses; and other economic, political or regulatory occurrences affecting companies in the real estate sector. REITs are also subject to the risk that the real estate market may experience an economic downturn generally, which may have a material effect on the real estate in which the REITs invest and their underlying portfolio securities. REITs may have also a relatively small market capitalization which may result in their shares experiencing less market liquidity and greater price volatility than larger companies. Increases in interest rates typically lower the present value of a REIT's future earnings stream, and may make financing property purchases and improvements more costly. Because the market price of REIT stocks may change based upon investors' collective perceptions of future earnings, the value of the Fund's REIT investments will generally decline when investors anticipate or experience rising interest rates. Because REITs are pooled investment vehicles that have their own expenses, the Fund will indirectly bear its proportionate share of these expenses.
Trading Issues Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
Valuation Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	VALUATION RISK. The Fund may hold securities or other assets that may be valued on the basis of factors other than market quotations. This may occur because the asset or security does not trade on a centralized exchange, or in times of market turmoil or reduced liquidity. There are multiple methods that can be used to value a portfolio holding when market quotations are not readily available. Fund investments that trade on non-U.S. exchanges that close prior to the close of the NYSE may be fair valued using a systematic fair valuation model. If these foreign investments meet certain criteria in relation to the valuation model, their valuation is systematically adjusted to reflect the impact of movement in the U.S. market after the close of certain foreign markets. The value established for any portfolio holding at a point in time might differ from what would be produced using a different methodology or if it had been priced using market quotations. Portfolio holdings that are valued using techniques other than market quotations, including “fair valued” assets or securities, may be subject to greater fluctuation in their valuations from one day to the next than if market quotations were used. In addition, there is no assurance that the Fund could sell or close out a portfolio position for the value established for it at any time, and it is possible that the Fund would incur a loss because a portfolio position is sold or closed out at a discount to the valuation established by the Fund at that time. The Fund’s ability to value investments may be impacted by technological issues or errors by pricing services or other third-party service providers.
Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	You could lose money by investing in the Fund.
Risk Not Insured Depository Institution [Member]
Prospectus [Line Items]
Risk [Text Block]	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.